The European Union’s policy on renewable energy is precisely defined in many documents, of which the most important 
established a framework for achieving the overall goals by applying effective strategies which were based on a close collaboration between the EU and its member states 
. The principles of this collaboration assume that actions aimed at the deployment of renewable energy need to be implemented at the national, regional, and local levels. It has been proved that the effective deployment of renewable energy particularly needs to be supported at the local level 
, and many concepts and models have been proposed to achieve it. Networking within the slow city concept can be considered as one of them.
The slow city concept, currently evolving into a green slow city concept, is fully in line with the need to support the deployment of renewable energy at the local level, and thus to help in achieving the green growth of Europe. It concentrates on endogenous resources, including natural ones, the needs and development of local communities, their cultural heritage, and the quality of life of present and future local generations 
. It assumes the protection and prudent use of natural resources, ecological education, social justice, and the cultivation of local production, often using traditional and ecological technologies 
The slow city concept has been adopted by the Cittaslow Network, established in 1999 and still undergoing development. At present, the network includes 278 municipalities in 30 countries (as of 30 June 2021). The Polish network of 35 Cittaslow municipalities is the second largest, while the Italian network is the largest of all 
. However, in the dispute on renewable energy deployment at the local level, there has so far been no reports regarding the Cittaslow Network attitudes and achievements in this field, leaving a gap in research.
2. Renewable Energy in the Development Strategies of Cittaslow Municipalities
The attitude of local governments to investments in renewable energy was assessed based on the analysis of the development strategies of Cittaslow municipalities, retrieved from the websites of municipalities in September 2021. The set of qualitative data contained information on all Cittaslow municipalities in Poland.
The findings show that 74.3% of local governments declared in their development strategies the use of renewable energy, and 68.6% identified concrete actions related to the deployment of renewable energy. Specific types of renewable energy are indicated only in the strategies of 28.6% of Cittaslow municipalities. Other strategies provided general information and indicated that renewable sources, also called alternative or green energy sources, should be used.
Among the 26 Cittaslow municipalities that indicated the need to develop defined types of renewable energy, only 10 referred to specific renewable energy sources. Strategies of 8 municipalities (22.9%) indicated the use of solar power, which is the most popular renewable energy source in Poland. Solar renewable energy is used to produce electricity for production and heating purposes, and it is processed using solar collectors and solar panels. Therefore, 22.9% of the strategies declared installation of solar collectors and solar panels.
Biomass and its different types were included in the strategies of 14.3% of Cittaslow municipalities, whose local authorities have stated that biomass energy is an important source of renewable energy. The strategies of 14.3% of Cittaslow municipalities include a declaration of investments related to wind energy. The strategies of 8.6% of Cittaslow municipalities include declarations of investments in geothermal energy.
The strategies stated that investments in renewable energy sources are of less importance due to the low population density, and it is not a priority for the municipality. There are also no proper conditions for the development of renewable energy, and little can be achieved in this regard. The strategies stated that with low environmental pollution, the potential investment costs related to renewable energy sources are disproportionate to benefits that can be obtained.
No strategy included any analysis or description of the conditions for renewable energy investments. Although the analyzed strategies did not indicate the sources and amounts of financing for renewable energy investments, their SWOT (strengths and weaknesses, opportunities, and threats) analyzes contained statements that the possibility of obtaining EU funds is a significant opportunity for the deployment of renewable energy.
3. The Implementation of Tasks Related to Renewable Energy Sources in Different Types of Cittaslow Municipalities and Correlation between the Renewable Energy Goals Included in the Strategies and the Practical Deployment of Various Types of Renewable Energy
The second part of the study on the diversification of renewable energy activities in Cittaslow municipalities was based on the analysis of qualitative data obtained in the survey. A total of 66% of the surveyed municipalities implemented activities related to solar renewable energy, and 23% to wind energy. The implementation of tasks related to geothermal energy (only 3 municipalities—8.6%) and hydropower (2 municipalities—5.7%) was rarely mentioned. Only one municipality indicated the implementation of tasks related to renewable energy from biomass. The analysis confirmed a strong variability of the obtained indications (coefficient of variation 88.6867, standard deviation: 0.9375). Respondents indicated the maximum of 3 activities supporting renewable energy deployment (3 municipalities). Additionally, 2 types of energy were indicated by 7 municipalities, one type of renewable energy—by 14, no type of renewable energy was indicated by 11 municipalities. The median is at 1, the arithmetic mean is 1.057.
The results indicate that the surveyed local governments took activities aimed at supporting the deployment of different types of renewable energy. Activities supporting deployment of energy from biomass was declared in only one of them—the one with the largest population. Solar energy activities were carried out in 7 Cittaslow municipalities with over 20,000 residents, 7 Cittaslow municipalities with less than 10,000 residents and 9 Cittaslow municipalities with a population between 10,000 and 20,000 residents. The largest share of municipalities supporting wind energy deployment has more than 20,000 residents (5 answers). Water energy activities were carried out in 2 Cittaslow municipalities whit a population between 10,000 and 20,000 residents. Geothermal energy was supported in 2 Cittaslow municipalities over 20,000 residents and in one Cittaslow municipality whit a population of 10,000–20,000 residents.
In order to determine the relationship between categories of Cittaslow municipalities and the types of deployed renewable energy, researchers applied Kruskal-Wallis test. The results confirm that the category of municipality has a significant impact on the deployment of solar energy (p < 0.05). There was no significant influence of the type of territorial unit on the implementation of tasks related to other types of renewable energy.
Spearman’s rank test showed a significant correlation between the type of municipalities and the implementation of tasks related to wind energy (rho = 0.393, p < 0.05). There is no significant correlation with other types of renewable energy.
The research results show differences between the declarations in strategies and the practical actions. The largest number of declarations related to renewable energy deployment can be found in the strategies in municipalities of 10,000–20,000 residents (53.8%), while most activities are carried out in municipalities with more than 20,000 residents (40.6%). There is a slight advantage of declarations in strategies (23.1%) over the implementation of tasks related to renewable energy (21.6%) in municipalities with a population below 10,000 residents.
The Spearman’s rank test did not show any significant correlation between the declarations in Cittaslow municipality strategies and the implementation of tasks related to renewable energy sources (rho = −0.239; p < 0.05). There is no significant correlation between the declarations in the strategy and the number of inhabitants in municipalities (rho = 0.278; p < 0.05). There is also no significant correlation between the type of Cittaslow municipalities (rho = 0.024; p < 0.05) and population.
4. Differentiation in the Implementation of Tasks Related to Renewable Energy Sources in Cittaslow Municipalities Depending on Their Socio-Economic Profile
The results of the research indicate that there were 24 Cittaslow municipalities which took at least one type of activities related to the development of renewable energy. They are classified in this study as ’the active’. Moreover, 11 municipalities did not indicate any type of renewable energy. Therefore, they were classified as ‘passive’. In total, the passive municipalities had over 142,000 residents, while the active ones more than 367,000 residents. researchers carried out a comparative analysis of selected socio-economic characteristics of these two groups, based on descriptive statistics.
The municipalities that declared the implementation of tasks related to renewable energy sources were characterized by a higher average value of the following indicators: budget revenues from personal tax in PLN per capita, budget revenues from corporate tax in PLN per capita, the ratio of economic entities per 10,000 residents, percentage of residents using sewage systems and from the water supply.
The age structure of the residents was similar in both groups. This applies to the share of people in pre-working age and the share of people in productive age. The average, minimum and maximum value of these indicators in municipalities belonging to both groups were at a comparable level.
A higher level of the number of social welfare beneficiaries per 10,000 residents and a lower ratio of economic entities per 10,000 residents in the group of the municipalities with low activity in the implementation of tasks related to renewable energy sources, may suggest that these municipalities are often have a lower level of economic potential than the active ones. This is also confirmed by the fact that the average size of the municipalities in the first group is 12,988 residents, and in the second 15,309 residents. The group of active local governments also includes the largest commune from the entire surveyed population.
5. The Quality of Life Synthetic Index of Cittaslow Municipalities and Its Correlation with the Local Governments’ Activities Supporting the Deployment of Renewable Energy
The Quality of Life Synthetic Index used to analyze the standard of living in Cittaslow municipalities ranged for the Cittaslow municipalities from 44.02 to 59.06. Its average level was 49.28, while the median was slightly lower at 48.43.
The group of 16 municipalities with 10,000 to 20,000 residents had the highest average quality of life index. This group of municipalities included those with the lowest (Węgorzewo) and the highest quality of life index (Murowana Goślina).
The group of 9 Cittaslow municipalities with more than 20,000 residents had a lower average value of the analyzed Quality of Life Synthetic Index. The lowest average value index was characteristic for the group of the 10 smallest Cittaslow municipalities i.e., with less than 10,000 residents. The maximum value of the indicator in this group was relatively the lowest It was in this group that the maximum value of the Index was the lowest—55.53.
Considering the distribution of responses on the number of supported renewable energy types in different categories of Cittaslow municipalities, it can be concluded that in the Cittaslow municipalities which implemented 3 types of activity, the average Quality of Life Synthetic Index was the lowest at 47.72. It was slightly higher in the group of municipalities that declared 1 type of activity at 48.44. In 11 Cittaslow municipalities that did not declare any tasks related to renewable energy sources, the Index was 49.84. The highest Quality of Life Index (50.78) was in municipalities that implemented 2 types of activities.
The Spearman’s rank test showed a significant correlation between the Quality of Life Synthetic Index in Cittaslow municipalities and their activities related to the development of wind energy (rho = 0.393, p < 0.05). There is no significant correlation with the other types of renewable energy deployed in Cittaslow municipalities.